[ltp] Re: T61, Lenovo quality, Linux pre-installed, alternatives

[Daniel Pittman]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> 1. battery only lasts about 5-6 hours for me compared to more than 7
>> hours on windows vista.
>
>> 2. area around fingerprint sensor gets too warm.
>
> The second probably explain a large part of the first.
>
> I've added the lines below to my /etc/sysfs.conf file for the same kind
> of reasons.  IIRC it saved me more than 1W on my T60:
>
>    # Hopefully, this is the fingerprint reader, which somehow isn't put
>    # into auto-suspend mode automatically by the 2.6.23 kernel :-(
>    bus/usb/devices/4-2/power/level = auto
>
> You'll want to first figure out which USB device is your fingerprint
> reader (maybe it's 4-2 like mine, but it may as well be anything
> else).

Sadly, for me, the USB layout changes between boots: sometimes the
fingerprint reader is 1-2, other times 3-2, presumably depending on the
order the root hubs enumerate or something.

In any case I implemented the following udev rule that sets the
'power' attribute to 'auto' when the device is detected by udev:

# Set the power mode of the fingerprint reader to auto, ensuring that it doesn't draw
# power that we otherwise don't care about.
SUBSYSTEMS=="usb", ATTR{manufacturer}=="STMicroelectronics", ATTR{product}=="Biometric Coprocessor", ATTR{power/level}="auto"

I hope that proves useful to others looking to use this; it certainly
makes the right palm rest significantly more pleasant for me to work
with.

Thank you, Stefan, for turning this up and letting us know.

Regards,
        Daniel